The present study examined the influence of children's experiences during non-maternal childcare on their behavior toward unfamiliar peers. Participants included children classified as negatively reactive at four months of age (N = 52) and children not negatively reactive (N = 61), who were further divided into those who experienced non-maternal care and those who did not. Children were observed during childcare at 24 months of age and in the laboratory with an unfamiliar peer at 24 and 36 months of age, where their wariness, dysregulation, and social engagement were assessed. Within the negatively reactive childcare group, children's positive interactions with peers during childcare at 24 months predicted lower levels of wariness toward an unfamiliar peer at 36 months. This relation was not significant for children not classified as negatively reactive. The findings suggest that the influence of non-maternal childcare is dependent on a child's temperament and on the nature of peer interactions during care.